Communicable by infection; easily diffused or spread from person to person or from place to place, as a disease, a moral influence, or a mental condition: specifically applied to diseases which are capable of being communicated from one to another, or which pervade certain places, attacking persons there, independently of any contact with those already sick. Infectious diseases include contagious and miasmatic diseases.Capable of communicating infection; that infects, taints, or corrupts; contaminating: as, infectious clothing; infectious air; an infectious vice.In law, capable of contaminating with illegality; exposing to seizure or forfeiture.Synonyms Catching, communicable.Contaminating, poisoning, defiling.